Oil refining



Sept. 17, 1940.

V J. ROBINSON OIL REIF'INING Filed March 10. 1932 mmzze Collector 44 h fi L H fi 40 INVENTOR- 1 I K Bobuzsom ATTORNEY Patented Sept. 17, 1940 UNiT-ED' STATES PATENT? OFFICE OIL DEFINING Jack Robinson, Wood River, 111., assignor to I Standard Oil Company, Chicago, 111., a corporation of V Application March 10, 1932, Serial No. 597,889

3 Claims. (o1. 106-147) combined effect of throwing the asphaltines outof solution, lowering the viscosity, and increasing the adsorptive eflficiency of the clay. A- further object is to provide a system wherein the-temperature in various parts, of an oil finishing system may be' easily regulated and maintained at a low value. Other objects will be understood from the following detailed description.

In practicing my invention I employ, as a diluent, a liquefied hydrocarbon gas such as propane or butane. I have found that the use of this diluent gives increased yields per ton ofclay inpercolation, and that an improved oil is produced thereby. At the same time the temperature and viscosity can be readily controlled and, by maintaining a suitable pressure on the system, the diluent may be carried with the oil and utilized in other steps of the finishing process. The diluent is particularly useful in regulating the temperature of the treating step, in producing the refrigeration for the dewaxlng step, and expediting the filtration of wax crystals; it will therefore be seen that my use of this diluent in the claying or percolation of the oil ties in with the other steps of the oil treatment to make a new and improved oil refining process.

The accompanying drawing, which forms a part of this specification, illustrates diagrammatically the plan of my improved system.

My invention is applicable to the refining of any lubricating oil, and it is particularly useful in refiningoils which are'contaminated by asphaltic, resinous or other impurities or coloring matters. In my specific example I will refer to the finishing of a heavy wax-bearing Mid-Continent lubricating oil having a viscosity of about 83 seconds Saybolt at 210 F. My preferred dilucm is a mixture of butane and propane having a vapor pressureat 100" r. of about 1004501113.

per square inch. It should be understood thatany of the liquefied hydrocarbon gases .or mixtures thereof may be used. with those hydrocarbons di-ificult to liquefy, the apparatusemployed must withstand higher pressures than. when the more easily liquefied hydrocarbons, such as butane, are

employed. The expression propane" in the following specification and claims is hereby defined to mean commercial propane or mixtures of propane with butane, having a vapor pressure at 100 F; of about 50-200 pounds.

' ii The lubricant 011 stock from storage tank I is forced by pump Hjthrough pipe E2 to mixer l3 at a pressure of about 50-200 pounds, depending upon the vapor pressure of the propane. Propane from pressure storage tank i4 is introduced by pipe l5 into pipe i2 and thence into the mixer l3. Treating acid, preferably 96% sulfuric acid,

in amounts of about one pound per gallon of oil stock, is introduced into the mixerthrough pipe It. The mixer itself mayconsist of a cylindrical drum provided with suitable perforated platen or baffles, the structure of which forms no part of the present invention. The temperature in the mixer is'preferably about 75-90 F. and it may be regulated by'the use of suitable heating or cooling coils.

The mixture of acid, 011 and propane is then' cient time is allowed for the reaction, and the sour oil is separated from the sludge in separator IS, the sludge being withdrawn through pipe l0.

Sour oil from the separator lBis conveyed by pipes 20 to clay contacting or percolating filters It is desirable that the temperature in the separator be kept within clearly defined limits, pref- .introduced into treating tank H, where sufil-,

erably about IO-90, and I accomplish this function by withdrawing vapors through pipe 22,

pump 23, and condenser 24, and returning the' propane back to storage tank ll. The cooling .in the acid treating chamber is thus effected by the vaporization of a portion of the diluent.

Percolating filters 2| may be of the conventional type wherein filter clay, such as fuller's earth, Attapulgus clay, Florida earth, etc., from 30 to 60 mesh is supported by screens and filter elements in large cylindrical chambers, each of which is provided with a hopper bottom. The

' chambers are adapted to withstand pressure upwards of 200 pounds and the upper part of each chamber is connected by conduits 25 through a pressure release valve 28 to vapor line 22.

I have discovered that the use of liquefied hydrocarbon gases as diluents in claying processes has important unexpected advantages. The liquefied gases seem to have a tendency to throw out asphaltines, asphaltic bodies, resins, and other coloringmatters and impurities from solution and to thereby assist in the adsorption of these i undesirable c mponents bythe clay. Of course, is

the propane has a marked eflect in reducing the viscosity of the oil which, in turn, brings about a marked increase in filter rates, avoiding harm- Iul and destructive temperatures. Another feature which is not easily explained is that a larger amount of oil may be treated with a given amount of clay when propane is used as a diluent or, in other words, the propane gives an increased yield of finished oil per ton of clay.

Oils which contain wax may be suitably dewaxed in propane solution either before or after the decolorization process.

Oil which has been neutralized, decolorized and purified by percolation in filters 2| may be introduced through pipes 21 into chillers 23, where- 'in additional amounts of propane may be added through pipes 29. In the chill chambers I prefer to have at least three or four volumes of propane to one volume of oil. Referigeration is effected by expansion of, propane vapors through pipes 30, compressor 3|, pipe 32, and condenser. 33 to propane receiver. I prefer to chill at the rate of about 2 or 3 per minute, the chilling rate being determined by the rate at which propane vapors are removed from the chillers.

When the temperature of the mixture in a chiller has reached about to 40 IE. it will be found that the wax has separated out in well defined readily filterable crystals, and the slurry is thereupon passed through pipes 34 and pump 35 to filters 36. These filters are of the closed type and are designed to operate at about-30 to 40 F. The filter structure per se forms no part of the present invention and it will not be describedindetail.

Wax is removed from filters by conduits 31 and the filtrate is removed therefrom through pipes 33 to filtrate collector 39. .It should be noted that pressure in the filters and the filtrate collector may be regulated by connecting. these elements'to vapor line 30 through suitable manually operated and/ or pressure relief valves.

The filtrate from the collector is passed by pipe 43, pump 4| and heat exchanger 42 into propane still 43, which is heated by suitable steam coil 44. Propane vapors are returned by pipe 45 to line 32, condenser 33 and storage tank l4. The finished oil is withdrawn i'rom the base in still 43 and is-passed through pipe 46 and heat exchanger 42.

. At intervals it is necessary to interrupt the action of a percolating filter so that the clay may be revivified or replaced. The oil maybe washed out or the filters at this time by means or propane and the propane may be entirely volatilized therefrom without the aid of stripping gases or stripping steam, The clay may be revivified by washing with caustic allgali and an alkali metal carbonate, as disclosed in Lowery 1,763,167, or it may be revivified with a solventmixture, as described in Lemon 1,805,178. In all of such cases the revivifying solution maybe washed out of the clay by means of propane even'ii the clay is rev disclosure is directed to those skilled in the art and therefore I have not described in detail the various valves, pumps, pressure regulators, etc., which may be used in the construction of the operating plant.

While I havedisclosed a preferred embodiment of my invention it will be understood that I do not limit myself to the details hereinabove set forth except as defined by-the following claims.

I claim: 7

1. The herein disclosed process of deoolorizing viscous lubricating oil which comprises heating a mixture 01 viscous lubricating oil and liquefied normally gaseous hydrocarbon solvent to a temperature corresponding to a solvent vapor pres sure inexcess of 150 pounds per square inch under pressure suflicient to maintain said solvent in the liquid state and passing the heated -mixture through 'a bed of adsorbent deoolorizing clay under suflicient pressure to maintain the heated solution in the liquid state.

2. The herein disclosed process of deoolorizing viscous lubricating oil which comprises heating a mixture of viscous lubricating oil and liquefied propane solvent under pressure sufilcient to maintain said solvent in the liquid state to a tempera ture corresponding to a solvent vapor pressure in excess of pounds per square inch and passing the heated mixture through a bed of adsorbent state through the bed of adsorbent deoolorizing clay during such periods of interrupted flow of oil solution.

- JACK ROBINSON. 

